Prior known multilocation video conferencing arrangements that have included switching video and audio signals to and from a plurality of locations have used analog signals. In more recent video conference arrangements, digital signals have been used for transmitting both the video and audio information to reduce the required transmission bandwidth. When using such digital signals it is desirable to obtain rapid switching of the video information from one location to one or more other locations in a conference without disrupting the audio information being received by the locations.
A straightforward way of switching video information with the presently used digital signals would require separate demultiplexing of the video information and audio information. A video switch is then obtained by a so-called remapping of the time slots of the digital signal including the video information from a location one time slot at a time into digital signals to be transmitted to the other locations. Then, the mixed audio for the particular location is combined with the remapped video for that location in a multiplexer.
One problem with such switching arrangements is the need for individual demultiplexers and multiplexers for each location. Moreover, since the video information is typically contained in a large number of time slots in one or more digital signals, the remapping process requires a similarly large number of operations. Consequently, the remapping process takes a lot of time during which the video being viewed at the locations and the audio being received are disrupted. These disruptions are extremely undesirable and should be avoided.